Head-up displays (HUDs) that allow an operator to view image information and an image of the scenery of the external environment by displaying various image information on a windshield of a moving body such as a vehicle, aircraft, etc., are known. For example, JP-A 11-271665 (Kokai) (1999) discusses technology regarding a head-up display that uses a liquid crystal display device.
In such HUDs, improvement of the ease of viewing while downsizing of apparatuses is necessary.